Any way for me to append my own affiliate link to existing links on my site? (1 post)

So I have a site where users are able to add their own links when using our service, this link is for more information and sometimes it is to a site that is selling their product/service. It is against our policy for these users to put their own affiliate links, but my question is if there is a way for me to append my own affiliate code to the end of their link?